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🔧 Feature Request: Enable Ironing on Support Interface Layers
Hi,

I’d like to suggest a feature improvement for OrcaSlicer regarding the ironing (surface smoothing) feature.

Currently, ironing is only applied to the topmost visible layers of printed parts. It would be extremely useful to allow ironing on the last layer of the support interface, i.e., the surface that directly contacts the printed part.

💡 Why this matters:
It would significantly improve the underside surface quality of supported areas.

By smoothing the support interface, we could reduce scarring, layer lines, and marks on the bottom of overhangs.

It’s especially helpful for parts where the bottom surface needs to be clean or make precise contact with other components.

Which printers will be beneficial to this feature?

All

Describe the solution you'd like

🔧 Suggested implementation:
Add a toggle in the support settings:

“Enable ironing on the last support interface layer”

Alternatively, allow per-object or per-support-zone ironing control, with ironing applied to interface areas only.

🙏 Thank you!
This small feature could make a big difference in FDM print quality, especially for professional or functional prototyping use cases.

Describe alternatives you've considered

No response

Additional context

No response